Fix The set of folders cannot be opened Outlook error

Fix The set of folders cannot be opened Outlook error. Outlook is the Office suite’s email and Calendar software which provides a wide array of features. Although started off as an email client (which it still is), people use it for managing tasks on the calendar, taking notes, arranging file backups, etc. An error commonly associated with Outlook, one that restricts you from accessing some of its folders and you see an error message that says “The set of folders cannot be opened.” This error can pop up on your screen unusually when you’re trying to launch Outlook. In this article, we will look at a few ways in which this issue can be remediated.

Why can’t I access my folders in Outlook?

If your Outlook data size is large, it may not be able to access or open the data files and folders. You need to reduce the Outlook data size or repair the Outlook installation.

Fix The set of folders cannot be opened Outlook error

This error usually indicates that the Outlook data file, which contains all the relevant information, cannot be opened. Make sure that the file isn’t being used by any other backup software when you encounter this error, as this will prevent Outlook from accessing it.

  1. Reset the Navigation Pane on Outlook
  2. Disable your Outlook Add-ins
  3. Reduce Outlook Data Size
  4. Recreate your Outlook profile
  5. Repair Microsoft Office

1] Reset the Navigation Pane on Outlook

Related Post: Outlook could not create the work file Check the temp environment variable

First try resetting your Outlook’s navigation bar using a run command.

Open the Run command with the Win+R shortcut key.
Please paste the following command and press enter:

outlook.exe /resetn avpane

There is a possibility that this might fix your problem, but if it doesn’t, you can try renaming the Outlook.xml file.
Paste the command in the Run prompt: Paste the following command in the Run prompt:

%app data%\Microsoft\Outlook

Microsoft Outlook app data folder: To access the Microsoft Outlook app data folder, right-click on Outlook.xml and select Rename. Enter its new name as ‘Outlook. old’. This will take you to the Outlook app data folder.
Open Outlook and check to see if the problem has been fixed.

This fix is, like the rest, only to be implemented if you have an Outlook account set up.

2] Disable your Outlook Add-ins

  • Open Outlook and go to File.
  • From the options pane on your left, select Options.
  • This will open the Outlook Options window. Here, select the add-ins you want to use.
  • Select the add-ins that you want to disable and save the changes.

You MUST update your Outlook version, To do so, open File > Office account > Office update. Click on Update options and then select Update Now.

3] Reduce Outlook Data Size

If the size of your mailbox is causing this error to occur, you can reduce the data size of its files by tweaking the Outlook options. Here’s how. To clean up your mailbox in Outlook, click on File, then Tools, and then Mailbox Cleanup.
There’s no need to single out anything – everything can be deleted!

You can clear the Deleted Items folder to reduce the size of the data file.

  • After you have finished on the File page, please click on the Account Settings.
  • From the list of files appearing on your screen, select the ones you want to compact.
  • Visit the File Settings > go to the Advanced tab > click on Outlook Data File settings and then select Compact Now.

4] Recreate your Outlook profile

If you’re having difficulties with Outlook, another potential solution is to recreate your profile. This could resolve the issue if there is any corruption present in your profile.

First, you will need to erase your profile data using the Registry Editor. To do this, open the Registry Editor and enter the following command line:


Depending on your version of Microsoft Office, you may have to use the following command line:Depending on the version of your Microsoft Office, you may have to use a different command line.


  • Delete all profile folders.
  • Now open Outlook and click on File.
  • Open the “Account Settings” drop-down and click on “Manage Profiles”.
  • Click Show Profiles, then click Add to enter a new user profile with your name.

Fill in the necessary credentials and save the changes.

5] Repair Microsoft Office

  • Open the Programs and Features control panel.
  • Here, find and select the Office suite option to repair it.
  • If the Quick Repair option doesn’t work, you can initiate the Online Repair too.

Relaunch Outlook to check if the issue has been fixed.

One of the aforementioned solutions can fix this issue for you, but if they don’t work, you can always reinstall Outlook on your PC.

Leave a Comment